Cooper Discoverer Radial STT Off-Road Radial Tire - 275/65R18 123Q The inner tread ribs alternating 3-2 pattern provides a number of significant performance benefits like: reduced road noise, increased stability and handling, superior soft surface (trail) and mud traction. The Discoverer STT PRO features large, specially-designed cleats of rubber (side biters) on the shoulder area of the sidewall, to enhance traction and grip. The flex groove provides a smoother ride by helping to dampen the impact generated by inconsistencies in pavement, potholes and gravel. The asymmetrical scallops on alternating lugs direct mud into the mud scoops to allow the tire to pull through muddy terrains with ease. ARMOR-TEK3 Carcass Protection provides 50% more protection against impact damage than standard 2-ply tires.